Development of a sensitive, yet ultra-low cost analytical system for determination of blood pathology such as thalassemia, sickle cell anemia, and microfilarial infestations is proposed. This technology is based on the principles of Field-Flow Fractionation and utilizes the simplest FFF system using only the Earth's gravitational field. While this G FFF (gravitational Field-Flow Fractionation) channel is simple, encouraging results for blood cell characterization have recently been produced by major efforts by researchers in France, supplemented by studies done by studies in the United States and Czechoslovakia. They have found that cells could be sorted by size and by density. Also, separation by the age (deformability) of the cells is possible. FFF separations were first demonstrated in the late 1960's. Since that time, applications to a wide range of biological components including proteins, DNA, monoclonal antibodies, lipoproteins, viruses, liposomes, bacteria, pollens, and blood cells has been performed in a few key laboratories. Widespread use of the technique has been somewhat prohibited due to the cost of instrumentation (in the range of $30,000 to $60,000). We hope to promote the FFF technique by introduction of an expensive system (@$5000). We propose to optimize channel materials, develop operation guidelines specific for blood cell characterization, and also to develop an inexpensive pump and detector which are needed for system operation. PROPOSED COMMERCIAL APPLICATION: The central focus of the proposed development is towards an inexpensive G FFF system with research and clinical applicability for blood analysis. This system should initially serve as an inexpensive screening tool in clinical labs, complementary to more expensive instrumentation. Also the availability of such a tool for sensing abnormalities of blood populations should appeal to the medical researcher.